Thatcher Calculator K & E Keuffel & Esser #4014 Pocket Watch Calculator / Slide Rule Larry & Carole Meeker
 * * * * * * *

           Antique Dealers & Brokers

Purveyors and Dealers of Americana  /  Patented & Mechanical Antiques

Antique & Vintage
Calculation Devices / Slide Rules & Related

We Buy or Can Help You Sell Your Scientific and Calculation Related Antiques &  Collectibles!!

We buy,sell, and deal in early and unusual slide rules, calculators and early patented calculation devices.  We also deal in many other Antique French Calculatoroffice related antiques and collectibles.   We specialize in tools and technology related antiques from the home, shop, farm, or office.  We are full time antique dealers of early scientific and technology related antiques and actively deal in a broad range of related antiques and related advertising.

This site, is our informational and past sales results website. There are links on the left to informational pages, and on the right are links to past sales results for many scientific related antiques we have sold.

Our antique sales site for these and other types of antiques and collectibles is  PleaseGordons 
	Addometer / Calculator visit it that site if you are looking to buy these types of antiques and collectibles.

Please contact us by email at if you have any interesting technological or scientific related antiques you want to sell, or want to cosign to us to sell for you.

Below are some pictures of the types of scientific antiques and vintage calculation devices and slide rules that we deal in and are seeking, along with some basic information to help you determine what you have.

Curta Calculators

The picture below is of the ever-popular Curta calculator.  The example pictured is known as a Type 1.  This step drum curta calculatorcalculator that was also produced as a Type 2 during the same time frame.  The main differences in the two calculators are that the type 2 Curta calculator has a larger capacity.  These calculating devices were first designed during WWII and were introduced shortly after the Second World War to the commercial market.  They were still being made right up to the time the hand-held electronic calculator caused their popularity to wane and production to end in the 70's  They originally retailed for about $150.00.  For most of the 70's and into the 80's examples sat on shelves and in back storerooms of drafting supply shops as dead stock for years.  Before the internet it was oftentimes hard to even get original retail for them.  Prices climbed and held steady for a number of years at around 200.  After word got out that they were being collected and a constant supply and demand became available on the internet, pricescurta calculator skyrocketed. 

Not too many years ago these devices could be had for a couple hundred dollars and there were more than enough to go around.  The supply seemed endless, and the demand scant.  The Internet auctions came and the market changed with a new group of collectors entering the market.  Prices initially went up to new unheard of levels and then back down after that initial demand was fulfilled and the tech bubble blew up.  They are still a popular collectible and demand is pretty constant with prices for them ranging anywhere from $600-2500.00 or so depending on a few variables including the serial #, condition and today it seems their heritage.  For example, I have nice Curtas listed for sale on our sales website for around $1200.00.  Results for French and German examples sold on eBay generally sell for $1500.00 - 2000.00 if you believe what you see. 

Antique Calculator Values

The prices of most later or more modern electronic calculators also took off for a while and reached new and unheard of Antique Adding Machinevalues when demand rose right after the internet came into vogue.  Many of those values dropped considerably after the tech bubble burst.  The value of these calculators seems to be tied to the amount of money folks of the proper age group have to spend as disposable income at any given time.  High when the stock market was doing well, and not so well after the bubble burst.

That scenario has repeated itself during this latest recession as well and I am willing to bet the same is true in relation to what happens in the Real Estate market.  Prices and interest rise in good markets and fall in bad.   I expect that things are going to be soft for a while.  It seems the only modern calculator to buck this trend are the examples of early Apple computers bringing 6 figures at auction. 

A market was also created by the internet for electronic hand-held calculators from our school days and evolved during this period also.  Another new collectible was born.  It seems that this category bubble went the same way as the lastSimplicitas
	Addizonartrice Adding Machine NASDAQ bubble as well.   I would bet a chart comparing the two price levels would look very similar.  The difference being that this may have been more fad than real.  Think Beannie Babies here.   I think it will be years, if ever, before some of the lofty heights that some of these later electronic calculation devices and other collectibles once brought is met again.   The one caveat being the rare of the rare still do well with the prime example being the Apple 1 computers selling for half a million or so.  Results like that are explained by some folks simply having too much money.

I like, and still look for these handheld electronic calculators, but rarely do I want the larger later and more typically seen  modern 10-key model calculators or adders, electric or mechanical, like those from the 30's or 40's or later.   Including large Victors, Burroughs, and a host of the other later 10-key heavyweight adding machines that seem to be in every garage and in every antique booth and even at the end of some ropes in the bottom of people's boats acting as ballast or anchors.  There are people who do collect and are looking for these later machines, but I do not know them and have no market to sell them.  Check eBay to see what most of these later 20's - 60's era calculators / adders actually sell for and you will see what I mean.

Early Calculation Devices

Antique and vintage calculating devices have had an interesting and varied period of development through the years.  Every Universal Adder Patented July 15th 1890one is familiar with the abacus, one of the earliest of all calculating devices. 

Another early form of a calculator first developed  for Western civilizations was known as Napier's Bones.  These were cubes or dice-like in shape, and were made  from bones or ivory and real examples are extremely rare and collectible.  They are being reproduced today and sold at various internet sites and auctions, at times with no indication of their true vintage.  Be aware.

Logarithmic scales found on slide rules were first introduced by Routledge in the early 1800's and were incorporated intoantique double wheel calculator the various forms of rules and other devices that were the forerunner to the slide rule as we know it today.  These scales were typically found on rules during the early to mid 1800's primarily for use by merchants and trades people who needed a viable way to run larger calculations for their lines of work or business.

One of the first types of mass produced calculating devices that still survive in numbers today are paper tables with  wheels and dials similar to the adder that is pictured above on the right.  The Palmer's Computing Scale (not shown) is the best known and most commonly seen of these types of early paper calculators.  Other variations do exist and are good pieces.

Early Dial type calculators / adders were around pretty much during the same period.  The best known of this style machine hart_caluculateris the well known Webb Adder which was  patented in  the late 1800's..  These were produced in a few different configurations throughout the years, with the earliest versions having a wooden back  On the right is the later version, this one being marked with the maker's name and patent date. There are early knockoffs of this calculator / adder that are not marked that can found as well.  They were produced to compete with the real things, much as the pirated tapes and CDs that abound in today's markets.

On the left  is a pretty rare and earlier model adder / calculator with this same basic configuration as those above.  It is known as the Hart Patent Adder.

I am interested in any of these kinds of early dial calculators,  sliding style calculators, or circularwebb-adder calculators like the one in the top left corner.

Please note that there is little market for newer sliding adders like those by the German firm Castell and the Japanese ones from the 1950's that were marketed after World  War II and sold from novelty catalogs and the back of magazines for a $1.00 or so.

I am an active antique dealer in early or antique calculation devices and looking to add nice examples to the sale pages on our sales website located at  I have a good selection of slide rules, calculators, adders and other early office and scientific antiques listed for sale there. Please take a look if interested in buying or selling.

Key Type Calculation Devices

Near the turn of the century dials began to give way to key type adders and calculators, or those with stepped drum and Burroughs Glass Side Adding Machine / Calculatorpinwheel style mechanisms, and when these stepped drum and pin-wheel models became more economically feasible to manufacture, even though they were invented years earlier they soon dominated the market.

This style calculating machine,  which quickly and easily performed four functions, became the standard.  Shortly thereafter calculators became electrified and all of these old style calculators were pretty much relegated to the status of obsolete but not necessarily collectible.  Millions had been produced and they are still readily available.

The story of the electronic calculator, and the design changes that they went through in a very short period of time until arriving at today's wonders of technological advances is a dramatic and interesting story. There is a very informative and well done site that is primarily focused on the history of the Hewlett Packard line of calculators, but they also have a very nice and well done history of earlier calculation devices leading up to the HP line.1st model wood comptometer A more detailed history of this period can be found at The Museum of HP Calculators.  It is interesting reading and should be looked into if you are trying to identify your calculator, or if this is the sort of thing that interests you. 

The most famous, and most commonly found early key style calculating machines is the Comptometer. It was a very popular machine in its day, as attested to by the sheer number that have survived and are still available. The most common versions are found in a tan metal case and sell for under $100 in most cases.  The earliest version came housed in a wooden case like the one pictured on the right and is much harder to find. These 1st model comptometers have been known to sell for several thousand depending on condition, serial number, and other factors.

Most 10 key machines by other makers that look similar to this with metal cases (like the Burroughs) are  considered very common and of little calcumter / adding machineinterest to me or to most other collectors of early calculating technology with limited storage space. Shipping costs outweigh retail value.

Other non electric calculators considered collectible operated with the  stepped drum or pin-wheel mechanism. Some of the names of these style machines are the Marchant, Odhner, Time is Money (TIM), The Millionaire Calculator, The Peerless Reckoning Machine which was sold by K & E, as well as a host of others that were being produced early on.  In general the earlier the better, with some selling for 1000.00 or more and others 100 or less. 

Slide Rules, Calculators
& Other Scientific Related Antiques

Below are some pictures of the types of scientific antiques and vintage calculation devices and slide rules that weFuller Calculator / Circular Slide Rule deal in and are seeking to K & E Webb Stadia Rule / Circular Sliderulebuy or help you sell.   I will provide some basic information to help you determine what you have and hopefully help you recognize some better and more desirable slide rules and calculators.

I am an active antique dealer interested in antique and collectible slide rules and other calculation devices that date from the early 20th century and before.  This page is a basic primer describing the different and various types of scientific and calculation devices we buy, sell, deal in, and can help you sell.

Keuffel & Esser Slide Rules

A Basic K & E Slide Rule Cursor Lesson or Beginning Primer for the Curious

The next three pictures give views of different early cursors (the sliding window portion) employed by Keuffel & Esser or K & E and  represent the transition or changes that slide rule cursors have gone through.  This is by no means the full story, and there are variations and other designs by other companies that are not covered here.  1st model Slide Rule cursor

The first picture of the all brass cursor on the right is referred to as the Christmas tree or chisel point cursor. This style cursor is considered the first model K & E used and dates from a bit before to near the turn of the 20th century.  It is rare and desirable. It can cause what is otherwise a $10.00 sliderule to sell for several hundred to $1000.00 or more.  It has no glass window like later model slide rule cursors do.  You would work off of one of the tips to do your calculations.  Some are like this one with the points going out to just one side and other K & E cursors have points on both sides of the center post or upright.   

The second clam shell cursor picture shows what is known as a clamshell cursor.  This was the second cursor employed by K & E. Some examples are pretty rare, others on common rules, are not.  

The clamshell design was replaced by the interesting looking and difficult to find column column cursor which is pictured below on the right.   The K & E Slide Rule column cursors still show in the 1913 catalogs, but were phased out shortly after that.  This cursor style was only used for a few short years and affects the value upward for most examples to levels in the hundreds of dollars on what would otherwise be a $10.00 - $20.00 rule.

K & E kept extensive records of their production and through research it is pretty well known how many of each type of cursor was offered and by scanning through the early catalogs when the cursor style changed and what models were offered when. 

The next cursor to be used after the column cursor was the short lived frameless cursor.   (not pictured here) This design was an attempt to save money and material and give the slide rule cursorK & E Column Cursor a sleeker look over the earlier designs.  It was a disaster as they were very fragile and prone to break at the connection points in the corners that had holes drilled through the glass.  This style cursor does not add much of  premium even though it is hard to find them not broken or damaged.

K & E shortly thereafter introduced the standard framed cursor that most slide rules found today have.  After K & E introduced their standard framed cursor, that basic design was used until production of slide rules ended in the late 60's or early 70's.

Slide Rules Wanted

I am interested in any slide rule with one of these early cursors pictured above, or slide rules with any other K& E / Keuffel & Esser 4088-2SM Slide Ruleunusual cursors that some other companies used.  Some of these had small decimal keepers or counters on them, or moveable arrows, or in one case a small abacus to help you along with your calculations and in keeping track of where the decimal point belonged. Some also had magnifiers built into the cursor.  K & E offered clip on magnifiers. 

I am also interested in any special use slide rules. Slides Rules with scales especially designed for surveying, chemicals, electrical calculations, aviation, and others are sought. There were many slide rules produced to help the scientist, machinist, shopkeeper, workers and others with the daily computations that they were faced with in performing their jobs.

Slide rules are an emerging collector category, and different folks collect them for different reasons.   Each of these groups feels that different ones are worth different amounts for different reasons.  If that seems confusing, it is, and prices and supposed values of these interesting collectables fluctuate wildly depending on which group you are listening to.  

Slide Rule Values

The first picture is of a relatively common but very collectable slide rule put out by K & E or Keuffel & Esser.  It is known as Decilon Slide Rule the Deci-Lon and was one of the last sliderules K & E  made or offered.  It is all plastic and was produced for a number of years, with the last models being designated by the model number 68-1100.  Before the Internet and the beginning of their "known" or documented popularity this rule could be had routinely for $20 or less and was routinely passed over by collectors and those in  the "know" who were looking for earlier and rarer examples of slide rules.  Today  this rule routinely brings $100 or so, not because they are scarce, but rather because they are popular. The 5" version sells for even more for the same reasons.  The collecting frenzy over them and the resulting prices they bring is largely driven by the same impulse that has created a desire for collectibles like GI Joes and Barbie dolls, that being the current generation buying back their childhood, and their memories rather than anything resembling scarcity or the historical significance associated with them.  In this case nerds as opposed to cheerleaders or jocks.

The point is that there are many earlier and somewhat rarer slide rules that are not having a lot of attention paid to them these days circular slide rulethat have potential to be worth more in the long run, and these are the rules that I am interested in.

Please Contact me with any early and unusual slide rule that you have and want to sell.  I can help you with it. 

I am also interested in other scientific or technology related antiques, including surveying instruments, other early calculation devices and early patented adders that date from the 19th century and into the early 20th century as well as a host of other related antiques. Please see those other pages in the left column to see or read more. I have many past sales results in the past sales archives that can be accessed through the link in the right column.

To see examples of many slide rules and calculators I have sold in the past please grrently have for sale please go to our sister site at and visit to see examples of similar antiques that we currently have for sale and visit the numerous sale pages you will find there. 

The above adders / calculators are an example of the caliber, condition and quality of these types of devices that we are primarily interested in.  To see examples of calculation devices we have sold in the past please look at the sales archive pages listed on the right.

If you have or know of one of these earlier and interesting adders / calculators that you want to sell please contact me at

To see examples of similar antiques that we currently have for sale please go to our sister site at and visit the numerous sale pages you will find there. 

Thank you!!
Larry & Carole Burkhardt Type A Arithmomete Marchant Type Mechanical Calculator

This website is Copyrighted
Larry & Carole Meeker